Discrete-time non-fragile dynamic output feedback H∞ controller design

The non-fragile dynamic output feedback H_infin controller design problem affected by finite word length (FWL) for linear discrete-time systems is investigated. The controller to be designed is assumed to be with additive gain variations, which reflect the FWL effects in controller implementation. A notion of structured vertex separator is proposed to approach this problem, and exploited to develop sufficient conditions for the non-fragile H_infin controller design via a two-step procedure. The resulting designs guarantee the asymptotical stability and the H_infin attenuation level of the closed-loop system. A comparison between our proposed method and the existing method for non-fragile H_infin controller design is provided, and a numerical example is carried out to support the theoretical findings.